Please amend the specification as follows: On page 12, in the first full paragraph on the page beginning with the phrase xe2x80x9cfrom the results reported abovexe2x80x9d, in the seventh line in that paragraph, immediately following the phrase xe2x80x9csome only work well onxe2x80x9d, delete the word xe2x80x9cenamelxe2x80x9d and substitute the word therefore xe2x80x9cdentinxe2x80x9d,
The present invention relates to tooth surface treatment composition and method. More particularly, the composition includes at least one water soluble acid in an aqueous solution, which may also contain tooth structure priming materials. A method according to the invention includes applying the composition to a tooth structure and subsequently applying dental adhesives and/or restoratives without the need to wash the composition from the tooth structure.
In tooth restoration the bonding strength of restorative dental materials to tooth structure including enamel and dentin, is of great importance. Insufficient bonding strength can cause loss of the restoration or formation of marginal gaps generating recurrent caries.
To achieve sufficient bonding strength, a tooth surface treatment is normally required. Phosphoric acid in concentrations of about 36% is widely used as demineralizes enamel prisms, thus promoting a mechanical anchor effect for the resin.
Using phosphoric acid as an etchant, sufficient bonding strength can be reached in combination with a suitable dental adhesive composition. However, the use of phosphoric acid has disadvantages from a use and application point of view. Most notably, it must be washed off after application, requiring the time-consuming procedure of application, washing and drying. Also, as it is completely removed after etching, it does not have any priming effect on the tooth surface.
A need exists therefore, for a material which will cleanse and condition a tooth structure and which does not need to be washed off of the structure before a dental restorative is applied. A need also exists for such a material which will not only cleanse and condition the tooth structure, but which will also prime it to receive the restorative. A further need is to provide this tooth surface treatment composition as a single component.
It is the object of the invention to provide a tooth surface treatment composition.
It is another object of the invention to provide such a material which will cleanse the tooth structure.
It is an object of the invention to provide such a material which will also condition the tooth structure to receive a dental restorative.
It is a still further object of the invention to provide such a material which will also prime the tooth structure to receive a dental restorative.
It is another object of the invention to provide a method of cleansing, conditioning and/or priming a tooth structure.
It is still another object of the invention to provide such a method which does not require that the primer/cleanser/conditioner be washed off of the tooth structure prior to a dental restorative being applied.
It is yet another object of the invention that this tooth surface treatment composite be provided as a single component so that mixing of two or more components is not necessary.
These and other objects of the invention, which shall become apparent from the description to follow, are achieved by the invention as hereinafter described and claimed.
In general, a tooth surface treatment composition according to the invention comprises an acidic component which comprises at least one water-soluble acid in an aqueous solution, such that when the composition is applied to the tooth surface it will increase the adhesiveness of the tooth structure without the need for washing the composition from the tooth surface. This composition can be provided as a single component material for ease of application and storage.
There is also provided according to the invention a method of treating a tooth structure which comprises the steps of: (a) physically contacting the tooth structure with a conditioner comprising at least one water-soluble acid in an aqueous solution; and, (b) at least partially drying the conditioner. The conditioner adheres to the tooth structure without the need for a washing step intermediate steps (a) and (b).
A method of adhesively restoring a tooth structure according to the present invention comprising the steps of: (a) physically contacting the tooth structure with a conditioner comprising at least one water-soluble acid in an aqueous solution; (b) at least partially drying the conditioner; (c) applying a dental adhesive to the tooth structure; and, (d) applying a dental restorative material to the tooth structure. The dental adhesive bonds to the tooth structure without the need for the conditioner to be first washed from the tooth structure.
The tooth surface treatment composition according to the present invention includes an aqueous solution of one or more water-soluble acids, preferably with an overall acid content of about 1 to about 50 weight percent, more preferably about 1 to 20 weight percent. The composition when applied to a tooth structure will enhance the adhesiveness of the structure without the need for washing. In addition, the composition may also contain additional components enhancing the priming, cleansing or conditioning effect of the composition, and as will be more fully explored hereinbelow.
The term xe2x80x9cdental adhesivexe2x80x9d and the like as used herein and as described in step (c) above, can apply to a wide range of materials which can effect a bond to both conditioned enamel and dentin. At a minimum, the dental adhesive contains a polymerizable resin component or components necessary to effect the initiation and acceleration of polymerization by visible or actinic light or by chemical means, and a polymerizable monomer or monomers containing an ionic functionality such as a phosphate or caboxylic (COOH) acid function. Preferably, this dental adhesive may be in the form of a self-priming adhesive which further contains a volatile solvent such as acetone, ethanol and mixtures thereof. Water may also be used as a solvent. The dental adhesive may comprise a one-component material, or may alternatively have two components. The second component of the dental adhesive may contain initiators and/or accelerators, to facilitate chemical curing alone or combined with curing upon exposure to actinic light to provide a dual-cure mode of polymerization. Examples of substances which facilitate self-curing of dental adhesives include for example, BPO, DHEPT and aromatic sulfinic acid salts.
Acids useful for the purpose of the invention are compounds which exhibit acidity when dissolved in water. Examples of acids include phosphoric acid, nitric acid, tartaric acid, maleic acid, itaconic acid, 5-sulfosalicylic acid, propionic acid, citric acid, hydrochloric acid, oxalic acid, latic acid. Especially preferred acids are maleic acid, itaconic acid, nitric acid and phosphoric acid, more particularly combinations of maleic acid and itaconic acid. One preferred composition contains about 3 to about 10 weight percent maleic acid and from 0 to about 9 weight percent (more preferably from about 2 to about 7 percent by weight) itaconic acid. Unless otherwise noted, all xe2x80x9cpercentxe2x80x9d, xe2x80x9c%xe2x80x9d and similar designations as used herein, refer to weight percent.
The tooth surface treatment composition may contain additional components enhancing the priming, cleansing or conditioning effect of the composition. Examples for substances with such effects are chemicals containing polymerizable double bonds such as those of methacrylic or similar groups; additional acids with good or limited solubility in water, surfactants and the like. More specifically, examples of useful priming components include alpa-methylene-gamma-butyrolactone, hydroxyethyl metacrylate, itaconic acid, ethyltriglycol methacrylate and 2-(methacryloyloxy)ethyl phosphate and the like.
The amount of water used is 100 weight percent less the total proportion of other contents, preferably 50 to 99 weight percent, more preferably, 80 to 98 weight percent. Distilled or deionized water is preferred, as it does not contain impurities potentially harmful to the adhesive properties of the solution. The composition may also contain 0 to 2 percent fluoride in the form of sodium fluoride or another fluoride compound.
A water compatible volatile solvent may be added to the composition, such as acetone, ethanol and mixtures thereof. When volatile solvents are used in the composition, the amount of water may be decreased to as low as 2 percent. The composition may also, optionally, contain a hydrophilic resin or monomer, such as for example, hydroxyethyl methacrylate (HEMA).
One preferred composition according to the invention includes from about 3 to about 12 percent by weight of an acidic component, from about 0 to about 10 percent by weight of a priming component, and the remaining amount to 100 percent by weight being water. A preferred acidic component is 5-8 weight percent maleic acid. A preferred priming component is 2-7 percent by weight of itaconic acid.
The aqueous solution of the acids may be applied directly to the wet tooth surface. After a specified time ranging from 5 to 100 seconds, preferably 10 to 40 seconds, the tooth surface is dried. Washing is not required.
After applying the tooth surface treatment composition, a photopolymerizable dental adhesive system may be applied, dried and light cured, followed by application and curing of a dental restorative material. Of course, a chemically cured adhesive may also be employed.
A preferred method of treating a tooth structure includes physically contacting the tooth structure with a conditioner as described above and including a priming component. The method also includes at least partially drying the conditioner from the tooth structure. Drying may be by any conventional means such as by air or forced air. The conditioner adheres to the tooth structure without the need for a washing step intermediate steps (a) and (b).
A method of adhesively restoring a tooth structure according to the present invention includes physically contacting the tooth structure with a conditioner as also described hereinabove, and preferably yet optionally containing the priming component. The conditioner composition is at least partially dried as above, and a dental adhesive is applied to the tooth structure. Following the adhesive a dental restorative material is applied to the tooth structure. The dental adhesive bonds to the tooth structure without the need for the conditioner to be first washed from the tooth structure.
The dental adhesives and restoratives used in the practice of the present invention are those conventional in the art. For example, one useful dental adhesive includes Prime and Bond 2.1 (available from Dentsply International Inc.). Preferred dental adhesives are cure by exposure to light, preferably visible light.
Useful dental restorative materials or cements include amalgam and non-amalgam dental restoratives. Examples of useful non-amalgam materials include compomer restorative, composite resin restorative, glass ionomer-resin restorative, glass ionomer-resin luting cement, resin cement and resin dental sealant. Examples of useful compomers are those having as a principle functional ingredient polymerizable unsaturated monomers of a substituted butane moiety with acid or reactive acid derivative functionality having the general formula (RO2C)xxe2x80x94C4H6xe2x80x94(CO2R1)y where R is an acid radical or a reactive acid derivative and Rxe2x80x2 is a polimerizable unsaturated radical having from about 2 carbon atoms to about 13 carbon atoms and xe2x80x9cxxe2x80x9d is 2 to 3 and xe2x80x9cyxe2x80x9d is 1 to 2. A description of such materials is provided in U.S. Pat. No. 5,218,070 which is hereby incorporated by reference for such disclosure. Examples of composite resin restoratives include T?H Spectrum available from Dentsply International Inc. Examples of glass ionomer-resin restoratives include Dyract available from Dentsply International Inc. Examples of glass ionomer-resin luting cements include Dyract CEM available from Dentsply International Inc. Examples of a resin cement include DICOR MGC Luting Cement and EnForce Resin Cement, both available from Dentsply International Inc. Examples of a resin dental sealant include Delton available from Dentsply International Inc.
One preferred dental restorative material is a two-component composite resin which is self-curable by chemical means, available from Dentsply International Inc. as ADAPTIC.